Refractory block



FIG. 1 is a front, perspective view of a refractory block showing our new design;

FIG. 2 is a back, perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a right side view thereof, the left side being a mirror image thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a back view thereof; and,

FIG. 7 is a bottom view thereof. 

The ornamental design for the refractory block, as shown as described. 